[daip] subim limitation

[Eric Greisen]

Lawrence Rudnick wrote:
>   I have an enormous cube from FARS, 400x8000x8000.    i want to do a 
> subim with yinc=5,zinc=5, but there's no way to input zinc.  transposing 
> and then subim'ing and then transposing back is an option, but the 
> transpose of the initial cube is a real bear.  i've managed a 
> workaround, doing partial subim first, then transpose to get other 
> axis.  since subim works on up to 7d images, incs might be better to 
> also go 7d.

We essentially never have more than 3 so ZINC should be enough.

The real issue is whether you would like the AVE, MIN, and MAX 
operations to work only in every ZINC'th plane or should they function 
in the full XINC x YINC x ZINC cube?  The former is easy, the latter 
will require a re-write of this ancient task but one I would not be 
entirely loathe to do.

Eric